JPH06165179A - Catv system - Google Patents

Abstract

PURPOSE:To reduce combined noise, to improve the quality of an UP signal and to reduce the cost of a bidirectional CATV system. CONSTITUTION:An internal transmitting antenna and an internal receiving antenna are respectively included in a subscriber's terminal equipment 6 and a communication control equipment 4 arranged on a transmisison line, a DAWN signal from a CATV center up to the equipment 6 is transmitted through a coaxial cable and an UP signal from the equipment 6 up to the equipment 4 out of all UP signals is wirelessly transmitted. The equipment 4 can receive UP signals from plural subscriber's terminal equipments. Since bidirectional communication can be attained by a system capable of preventing the generation of combined noise and communication in a single direction can be adopted in the wired part from the equipment 4 to the terminal part, the adoption of this CATV system for a bidirectional CATV system in an existing multiple dwelling house can be attained at a low cost without modifying the equipment of the house.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a CA comprising a plurality of subscriber terminal units, a central control unit and a transmission line connecting them.
It relates to a TV system.

[0002]

2. Description of the Related Art In a conventional CATV system, when a subscriber terminal device sends an upstream signal to a CATV center, the upstream signal is frequency-multiplexed via a cable for receiving a downstream video signal and a control signal from the CATV center. Was sent out.

In addition, as a transmission path for upstream signals, CATV is used.
Even when a cable is not used, a telephone call is sequentially issued through a telephone line and an upstream signal is sent to a CATV center after the line is connected (for example, Japanese Patent Laid-Open No. 3-22719).
0).

[0004]

[Problems to be Solved by the Invention] Such a conventional CA
In the TV system, since all subscriber terminal devices are connected to the cable, jump noise generated near each subscriber terminal device is accumulated near the CATV center and becomes a large noise, which is a so-called ingress noise that hinders signal communication. Was a cause of the occurrence of. Also, in most existing housing units, the audible reception equipment is mostly unidirectional equipment, so
When connecting to the system, there were major problems in measures against jumping interference and bidirectionality.

Further, in the method of transmitting the upstream signal via the telephone line, since the telephone is sequentially called and the upstream signal from the subscriber terminal device is sequentially collected after the line is connected, the upstream signal is transmitted from the CATV center. There was a problem that I could not collect it immediately.

[0006]

In order to solve the above-mentioned problems, the present invention is from the subscriber terminal device to the communication control device installed on the transmission path in the route of the upstream signal transmitted from the subscriber terminal device. Is performed by wireless communication.

[0007]

As described above, the present invention wirelessly transmits an upstream signal transmitted from a subscriber terminal device, receives this signal by a communication control device installed on a transmission line, and further from this communication control device. By sending out to the CATV center via the cable, noise generated near the subscriber terminal can be reduced.

Further, since the cable transmission line from the communication control device to the subscriber terminal device can remain unidirectional, the facility construction cost and maintenance cost can be reduced, and the existing housing complex can be CATed.
Even when incorporating into the V system, the existing equipment remains unidirectional and enables connection to the CATV system at low cost.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram in one embodiment of the present invention,
2 is a block diagram of a subscriber terminal device, and FIG. 3 is a block diagram of a communication control device.

Downstream video and control signals sent from the CATV center 1 are transmitted via the trunk coaxial cable 2 to the bidirectional amplifiers 3.1 to 3. It is sent to the communication control device 4 via n. Further, each of the subscriber terminal devices 6.1 to 6. in the housing complex is connected from the communication control device 4 via the coaxial service line 5. distributed to n. As described above, the downlink signal is sent to the subscriber terminal device through the trunk line 2 and the drop line 5 which are coaxial cables.

On the other hand, an upstream signal transmitted from the subscriber terminal device 6 to the CATV center 1 is wirelessly transmitted from the subscriber terminal device 6 and received by the communication control device 4. Then, from the communication control device 4 to the trunk coaxial cable 2,
It is sent to the CATV center 1 via the bidirectional amplifier 3.

At the CATV center 1, each subscriber terminal device 6.1 to 6. When collecting the upstream signal from n by the polling method, first, the central control unit placed in the CATV center 1 sends an upstream data request signal to the subscriber terminal device 6.1 via the coaxial cable. The subscriber terminal device 6.1 that has received the request signal sends an upstream signal to the communication control device 4 by radio of a specific frequency. The communication control device 4, which has received the upstream radio signal, converts this signal to a frequency that can be frequency-multiplexed on the CATV trunk coaxial cable, and then sends it to the CATV center 1 via the CATV trunk. This upstream data is sent to the central control unit of the CATV center, and the polling of one subscriber terminal device is completed. This operation is performed by another subscriber terminal device 6.2.
6. It is possible to poll all subscriber terminal devices by repeating the process for n.

Still another polling method is CA
From the TV center 1 to each communication control device 4, subscriber terminal devices 6.1 to 6. There is a method of notifying the address of n, storing the address internally by the communication control device 4, and independently polling the subordinate subscriber terminal device for each communication control device. In this polling method for each group under the communication control device, the CATV center 1 sequentially polls only each communication control device and polls the subordinate subscriber terminal devices so that only the communication control device in which upstream data is generated. Since it is also possible to receive the upstream data, it is possible to reduce the traffic of traffic on the trunk line and to improve the polling frequency for each subscriber terminal device.

In any of the above cases, one communication control device wirelessly communicates with a plurality of subscriber terminal devices, but the frequency of the upstream radio signal from each subscriber terminal device may be the same frequency. Therefore, the wireless reception unit of the communication control device 4 can be configured by a simple circuit.

Next, the configuration of the subscriber terminal device according to the embodiment of the present invention will be described with reference to FIG. The signal input from the CATV input terminal 7 is divided into a video signal 9 and a data signal 10 by the demultiplexer 8. Video signal 9 is tuner 1
An arbitrary wave is selected by 1 and output to the output terminal 12 to be sent to the television receiver. On the other hand, the data signal 10 is demodulated by the demodulation unit 13 and taken into the microcomputer 14. This microcomputer 14
Together with the control of the tuner 11 and the control of the receiving unit 16 that receives the signal sent from the remote control unit 15,
The downlink control signal from the center is received, and the viewing condition of the subscriber terminal device is also controlled if necessary. Further, when transmitting an upstream signal, the upstream data is sent to the wireless modulation unit 17, and the modulated signal is wirelessly transmitted from the internal transmission antenna 18.

FIG. 3 is a block diagram of a communication control device in an embodiment of the present invention. The downstream signal input from the bidirectional connection terminal 20 is divided into a video signal 22 and a data signal 23 by the demultiplexer / mixer 21. The data signal 23 is demodulated by the modulation / demodulation unit 24 and taken into the microprocessor 25. When the subordinate subscriber terminal device address is sent as a data signal from the central control unit of the CATV center, this address is stored in the memory 26. If there is upstream data to be transmitted from the communication control device to the CATV center, the data is modulated by the modulation / demodulation unit 24 and then transmitted to the demultiplexing / mixing unit 21 and the CATV from the bidirectional connection terminal 20.
It is output to the center 1 via a coaxial cable.
When the communication control device polls the subordinate subscriber terminal device, an image data request signal is output from the microprocessor 25, modulated by the modulator 27, and then demultiplexed by the demultiplexer / mixer 21. The signal 22 is mixed with the mixer 28 and delivered from the downstream output terminal 29 to each subscriber terminal device through the drop line.

On the other hand, the upstream radio signal transmitted from the subscriber terminal device is received by the internal receiving antenna 30, demodulated by the radio demodulation unit 31, and taken into the microprocessor 25. The microprocessor 25 sends the upstream data to the CATV center as needed.

[0018]

As described above, according to the present invention, in the upstream signal of the CATV, the portion from the subscriber terminal device to the communication control device is made wireless, so that the downlink transmission is a conventional cable having a good transmission quality. On the other hand, the upstream transmission, which has a problem of upstream ingress noise, is a wireless system in which ingress noise does not occur, and only one direction from the subscriber terminal device to the communication control device needs to be wireless. An interactive CATV system can be realized by a cost-effective method.

Further, the communication control device can receive upstream signals from a plurality of subscriber terminal devices. For example, in an existing housing complex, it is possible to install one communication control device for each house. It is possible to easily connect to an interactive CATV system of an existing apartment house, which was difficult to incorporate, at low cost.

[Brief description of drawings]

FIG. 1 is a block diagram of a CATV system according to an embodiment of the present invention.

FIG. 2 is a block diagram of a subscriber terminal device.

FIG. 3 is a block diagram of a communication control device

[Explanation of symbols]

 1 CATV Center 2 Main Coaxial Cable 4 Communication Control Device 5 Drop-in Coaxial Cable 6 Subscriber Terminal Device 13 Downlink Signal Demodulator 17 Uplink Radio Modulator 18 Internal Transmit Antenna 27 Downlink Data Signal Modulator 30 Internal Receive Antenna 31 Uplink Radio Signal Demodulator Department

Claims (2)

[Claims] 1. A CATV system comprising a plurality of subscriber terminal devices, a CATV center for transmitting data to the subscriber terminal devices, and a transmission line connecting them.
A communication control device for remotely controlling the subscriber terminal device is provided on the transmission path, wired communication is performed between the CATV center and the communication control device, and between the subscriber terminal device and the communication control device. Is a wireless transmission path and a wired transmission path, and a video signal and a control signal sent from the communication control device are received via a cable and sent from the subscriber terminal to the communication control device. Is a wireless communication method. 2. The communication method according to claim 1, wherein the CATV center polls a communication control device, and the communication control device performs group polling on a plurality of subscriber terminal devices under the control.